Re: [CAD_CAM_EDM_DRO] Uni vs. Bi - polar stepper in router

In a message dated 27-Oct-00 15:54:54 Central Daylight Time,
r_fl_z@... writes:

<< Is the use of Unipolar steppers very common in cnc router table designs,
particularly in routers of the home variety? Or, do most use a Bipolar
chopper for the efficiency and power? >>

Ron: At the outset, may I admit I are ignernt and sloven. Having said that,
I assert that I have "been there, done SOME of that". Some older designs
surely were "unipolar" with 6-lead motors. Surely, recent "state of the art"
designs use bipolar (4-lead motors) exclusively? (One can never know, as
there are surely old folkes out there who feel "if it worked for my
grandfather, it is surely good enough for me!")

X-Y table? I built a HUGE X-Y table in '85-'86, for an English firm, using
the-then "latest" Superior Electric motors and drives. These were "chopper
drives", but I do not recall if they were "unipolar" or not. I think they
were, however, best my old mind can recall. Then, Warner/Dana bought S.E.,
and I assume the median-age of their engineering-department went down by at
least a decade, and bipolars appeared in their offereings. Drives, too.
Nice stuff.

Thus, surely any "current products" or "new designs by engineers less than 60
years of age" will be bipolar?

Some sophisticated "professional" woodworking machinery is being made by
firms such as Thermwood, etc. I know of some "Home Brew" and "made by local
firms" stuff which is, well, "challenged". But there is an (initial!)
price-difference between these latter concepts and some of the
wrinkle-finished top-of-the-line "professional" stuff! If you are asking for
your own information, to facilitate building something yourself, GO for
bipolar-chopper!

Jan Rowland, Troll